As an IT professional, one thing I hate is meaningless error messages. Check out this post from Seth Godin on his experience using the NY DOT's web site.
The developer has made a major mistake in allowing an internal database error message to be displayed to the user rather than writing a few lines of code to catch the error and display something more meaningful to the user, which in this case would be: "the phone number you have entered is in the wrong format".
How does this happen? My guess is that somewhere in this organisation is a pointy-haired boss whose idea of getting the project on track is to start writing code as soon as possible. So instead of thinking about things like "what errors could happen and what (meaningful) message should I display to the user when they do," everyone just rushed off to write code.
In this case it's even worse, because with a little thought up front, the error could have been prevented. All it would have taken is a small prompt to tell the user what format to use. As someone who works all over the world I particularly hate this with dates where September 11 2001 can be written 9/11/01, 11/9/01 or 01/09/11 when all it takes is a label next to the date entry box to tell me DDMMYY or YYMMDD or whatever.
As I said in a recent post, crap is still everywhere.